How to reproduce:
1) Minimize all other application eventually running, leaving only MM in non-maximized mode;
2) Resize MM window to make it 850x600px or less, like in screenshot below;
3) Connect any media device to your computer and go to its node in Media Tree, so the Summary tab shows up;
4) Minimize the restore MM window.
A transparent area appears at lower/right side of window, showing desktop background.

